跌流竖井内循环气流流通的临界位置理论建模和计算

在跌流竖井中设置内循环气流系统能够有效减缓下游排水管道被加压和气体聚集的状况.为了确定内循环气流系统中气体能够形成流通回路的临界位置,采用理论模型计算的方法研究了带有内循环气流系统的跌流竖井内湿管和气管的气压分布.结果表明:只有当气体循环路径在高于临界气压所对应的临界位置时,该内循环气流系统才能够发挥作用;理论计算所得湿管和气管的气压分布与模型实验所测得的数据相吻合;对于跌落高度为7.72 m的跌流式竖井,临界位置的范围为0.65~0.84倍跌流高度,且流量越大临界位置越靠近竖井底部.

Theoretical modeling and calculation of critical position of internal circulation air flow in a plunging-type dropshaft

The installation of an internal air circulationflow system in the plunging-type dropshaft can effectively slow down the air pressure and air accumulation in downstream drainage pipelines. In order to determine the critical position where the air in the internal air circulation flow system can form a circulation loop, the theoretical calculation method was used to explore the pressure distribution in the wet shaft and the air shaft in the plunging-type dropshaft with an internal air circulation system. The results showed that the system played an effective role only when the air-circulated route was above the critical position (corresponding to the critical pressure). The calculated air pressure distributions in both shafts through the theoretical calculation method agree with the measurements well. For the plunging-type dropshaft with a drop height of H = 7.72 m, the critical position was about 0.65H ~ 0.84H. Moreover, the critical position was closer to the bottom of the dropshaft with the increase of the water flow rate.